This application has been filed in the United States Patent and Trademark Office under 35 U.S.C. xc2xa7371 based on International Application No. PCT/US99/23228 having an international filing date of Oct. 5, 1999 and claiming a priority date of Oct. 7, 1998 based on Mexican Serial No. 9808284. The International Application was published pursuant to the Patent Cooperation Treaty under International Publication No. WO 00/20774 on Apr. 13, 2000 (International Publication Date).
1. Field of the Invention
This invention relates generally to springs used in automotive suspension systems, and more particularly, to springs for use in the rear suspension system of a vehicle.
2. Description of the Related Art
Springs that are presently in use in the suspension systems of vehicles are formed of two parallel elongated sheets, or leafs, manufactured of spring steel, such as SAE 5160, 6150, JSAE SUP 9, and are of the type that are centrally joined by a bolt or a retaining clamp that is installed near one of the ends of the spring. The bolt functions to keep the two spring leafs in joined condition, while the retaining clamp avoids the spring leafs from becoming laterally displaced with respect to each other, whereupon the ability of the springs to support the vehicle would be diminished. In addition, such lateral displacement of the springs may result in one of the spring leafs hitting a part of the vehicle, such as a hose or the gas tank, creating a dangerous condition during the use of the vehicle. Placement of the retaining clamp is effected upon fixing same with a rivet to one of the spring leafs, placing thereon a series of inserts, and closing the rivet with the use of a press or a hammer or mallet. Clearly, the installation of the retaining clamp is a labor intensive operation that requires adherence to dimensional and tolerance specifications.
In view of the foregoing, it is an object of this invention to eliminate the use of a retaining clamp for maintaining the lateral edges of two spring leafs parallel and in alignment.
It is also an object of this invention to eliminate the need for a retaining clamp while nevertheless achieving a comfortable ride in the vehicle as the vehicle is operated over holes and bumps.
It is another object of this invention to provide a spring having resistance, capacity, and durability characteristics that remain similar to those of known springs.
It is still another object of this invention to provide a spring arrangement that affords savings in labor and material by eliminating the need for a conventional retaining clamp.
The foregoing and other objects are achieved by this invention which provides, in accordance with a first apparatus aspect thereof, a suspension spring arrangement for a vehicle. The suspension spring arrangement is of the type having an upper elongated spring leaf, a lower elongated spring leaf, and clamping bolt or other fastener disposed in central area of the upper and lower elongated spring leafs. The clamping bolt joins the upper and lower elongated spring leafs to each other. In accordance with the invention, there is provided a slot arranged in the vicinity of an end of the upper elongated spring leaf. A protuberance that is formed near an end of the lower elongated spring leaf is formed of a portion of the lower elongated spring leaf itself The protuberance is defined by a cut in the lower elongated spring leaf and the material defined thereby is bent so as to be directed substantially orthogonal to a surface of the lower elongated spring leaf. The protuberance is disposed to be accommodated within the slot of the upper elongated spring leaf so as to prevent lateral displacement of the upper and lower elongated spring leafs with respect to each other.
In one embodiment of this first aspect of the invention, there is provided an insert that is disposed between the slot and the protuberance for avoiding impact and squeaking noises. The insert may be formed of a polymeric material, such as nylon, Teflon(copyright), polyethylene, and polyurethane.
In other embodiments of the invention, the protuberance and/or the slot is configured in a variety of selectable shapes, depending upon the use that is made of the suspension spring arrangement. For example, the slot and protuberance may be configured to have square, rectangular, and/or circular configurations.
In accordance with a further apparatus aspect of the invention, there is provided a suspension spring arrangement for a vehicle, the suspension spring arrangement being of the type having an upper elongated spring leaf, a lower elongated spring leaf, and a clamping bolt disposed in a central area of the upper and lower elongated spring leafs, whereby such spring leafs are joined to one another. In accordance with the further aspect of the invention, there is provided a first slot disposed near a first end of the upper elongated spring leaf, and a second slot disposed near a second end of the same spring leaf. A first protuberance is formed near a first end of a lower elongated spring leaf, the first protuberance being formed of a first portion of the lower elongated spring leaf that is defined by a first cut and a corresponding portion thereof is directed substantially orthogonal to the lower elongated spring leaf. Similarly, a second protuberance is formed near a second end of the lower elongated spring leaf. When the upper and lower elongated spring leafs are joined to one another, the first protuberance is disposed to be accommodated within the first slot of the upper elongated spring leaf Similarly, in other embodiments, the second protuberance is accommodated within the second slot of the upper elongated spring leaf.
In one embodiment of this further aspect of the invention, there is provided a first insert disposed between the first slot and the first protuberance. As previously noted, such an insert eliminates impact and squeaking noises between the first slot and the first protuberance. In similar manner, a second insert is disposed between the second slot and the second protuberance. Also, as previously noted, the first and second slots, and the first and second protuberances, are configured in accordance with selectable ones of square, rectangular, and circular shapes.
In accordance with a method aspect of the invention, there are provided the steps of:
punching at least one slot near an end of a first spring leaf (12);
forming a protuberance near an end of a second spring leaf (14) by forming a partial cut and folding a portion of the second spring leaf (14) to be substantially orthogonal to the second spring leaf (14); and
joining the first and second spring leafs at respective central portions thereof with a fastener whereby the protuberance of the second spring leaf (14) is accommodated within the slot of the first spring leaf (12). In this manner, lateral displacement of the first and second spring leafs with respect to each other is precluded.
In one embodiment of this method aspect of the invention, there is provided the further step of installing an insert between the protuberance of the second spring leaf and the slot of the first spring leaf. In one embodiment, the installation of such an insert is performed before performing the step of joining the first and second spring leafs to one another.